1. Field of the invention
This invention relates to an integrated brake and chain disk assembly for a door operator, particularly to an integrated brake and chain disk assembly for a door operator by which a main shaft of the door operator can be braked and rotated by arrangement of a torsion spring.
2. Brief Description of the Prior Art
Generally, the door operator for a fire door or a safety door basically comprises an electric motor with a main shaft coupled to a gear box for rolling a rolling door such as a flexible sheet door, a slat door, a grille door and the like; a brake device having at least one end disk for braking the main shaft; a chain disk device for manually rotating the main shaft upon power failure; and a clutch device for disengagement of the end disk by energizing an electromagnet. Further, the door operator additionally includes a latch device for locking the chain disk in the motor operation mode; and a brake releasing device for releasing the brake device in the manual operation mode. For the manual operation mode, it is well known that the latch device has to be released at first, and then a chain is pulled on one hand while the brake releasing device is operated so as to release the main shaft in other hand.
As to an integrated brake and chain assembly for a door operator, several associated documents have been proposed. For example, U.S. Pat. No. 6,055,885 which was filed by the applicant describes that the chain disk is used for manually rotating the main shaft upon power failure and normally pressed against a clutch device by means of an elastic element so as to brake the main shaft of the door operator. Therefore, a latch device for locking the chain is provided on the housing of the door operator so as to hold the chain disk. Furthermore, U.S. Pat. No. 6,092,582 has a typical operation mode as stated above where a latch device has to be released at first in the manual operation mode, and then the chain is pulled so as to rotate the chain disk and at the same time the brake releasing device has to be operated so as to release the main shaft.
Additionally, the applicant's another U.S. Pat. No. 7,055,283 B2 has been proposed to provide a control system for switching from a manual operation mode into a motor operation mode, comprising a brake device for braking and releasing a main shaft of the door operator; a chain disk device pivoted uncoaxially; a clutch device disposed between the main shaft and the chain disk device for allowance of rotation in single direction; a driven disk interlocked with the clutch device for switching a protection device. As long as the chain is pulled, the circuit of the door operator is cut off and the braking device is released so that the operation mode is automatically switched into a safe manual operation mode.
The person skilled in the art understands that the above documents still need to be improved when put into practical.